1. Field of the Invention
The present invention relates to air-conditioning apparatuses and, more particularly, it relates to an air-conditioning apparatus that, without a sensor provided to detect the presence of an occupant in a room, provides variable control of the direction of an air blow vane or the air flow speed or air volume of a fan associated with heating operation according to the circumstances.
2. Description of the Related Art
Some known air-conditioning apparatuses perform control so as to set the air blow vane on the indoor unit air outlet to a downward direction or increase the air volume of the indoor unit fan if there is a high likelihood that there is no occupant in the room when a timer or home control is activated (see, for example, Japanese Unexamined Patent Application Publication No. 61-223448). This is intended to speed up a rise in room temperature during heating operation if there is no occupant in the room.
In contrast, indoor units of other apparatuses are provided with a sensor, such as an infrared sensor, for detecting the presence of an occupant and, if such a sensor detects that there is no occupant in the room, the other apparatuses perform control so as to set the air blow vane to a downward direction or increase the air volume of the fan (see, for example, Japanese Unexamined Patent Application Publications Nos. 2004-150731 and 2008-101874).
In particular, the air-conditioning apparatuses disclosed in Japanese Unexamined Patent Application Publications Nos. 2004-150731 and 2008-101874 are configured to set the air blow vane to a horizontal direction if there is an occupant in the room so that the occupant is not directly exposed to cold or warm wind, thereby giving comfort to the occupant.
However, an air-conditioning apparatus disclosed in Japanese Unexamined Patent Application Publication No. 61-223448 performs control so as to set the air blow vane to a downward direction or increase the air volume of the fan when a timer or home control is activated. For this reason, even if an occupant is actually present in the room, such an air-conditioning apparatus performs control so as to set the air blow vane to a downward direction or increase the air volume of the fan when a timer or home control is activated, which makes the occupant in the room uncomfortable.
In contrast, like air-conditioning apparatuses disclosed in Japanese Unexamined Patent Application Publications Nos. 2004-150731 and 2008-101874, a system provided with an infrared sensor for detecting the presence of an occupant in the room can exactly detect the presence of an occupant. However, such a system becomes costly due to the use of such an expensive infrared sensor. In addition, in order to provide a highly precise detection, an optimum sensor mounting position must be selected with keeping structural and design restrictions in mind, resulting in increased cost of the air-conditioning apparatus main unit itself.